The delivery of data using the cable television (CATV) system has become common in residential areas where CATV is commonly available. The data are delivered both downstream and upstream using available channels and/or frequencies. The end user can connect to the data systems through a cable modem that is capable of delivering the downstream data respective of the specific user to that user, as well as sending upstream data sent by the user which is intended to reach another node of the data network.
Because providers of CATV expect to deliver additional services, such as data for Internet connectivity, there is an interest to serve as large as possible number of clients. However, it is not always possible to provide a direct connection to each location. For example, a shopping mall near a residential area is not commonly wired for the use of CATV as the necessity of such is quite low. FIG. 1 is a diagram which shows the distribution of CATV to a residential area. Clients use a cable modem to have access to downstream data and to transfer data upstream. If the CATV operator would like to provide a service to clients in the shopping mall a distribution coax cable would have to be laid at a significant cost.
Some cable modems are compliant with Data Over Cable Service Interface Specifications (DOCSIS), which are interface specifications for standard, interoperable, data-over-cable network products. Internet Service Providers (ISPs) using the Multichannel Multipoint Distribution Service (MMDS) may also be compatible with DOCSIS. However, current MMDS networks are not entirely satisfactory. MMDS networks are characterized by the limited number of channels available in the low radio frequency (RF) bands. Only 200 MHz of spectrum (between 2.5 GHz and 2.7 GHz) is allocated for MMDS use. This constraint reduces the effective number of channels in a single MMDS system.
Moreover, the MMDS wireless cable uses 6 MHZ television channels for upstream and downstream transmission. These channels are relatively closely spaced in frequency. Because the channels are so closely spaced in frequency, a diplexer is required at each subscriber location to separate the upstream transmission path and the downstream receive path. Thus, the processing equipment required, including the diplexer, is relatively expensive and cumbersome. And, the up to two 6 MHZ channels which may be allocated to the reverse direction are the maximum frequency spectrum, which is a significant limitation. In addition, because the MMDS channels are licensed, the ISP must go to the expense of purchasing or leasing a license that could cost in the millions of dollars.
Fortunately, in 1997 the Federal Communication Commission (FCC) set aside 300 MHz of spectrum in the 5 GHz band for the Unlicensed National Information Infrastructure (U-NII) service. Three bands are defined in this spectrum: 5.15 to 5.25 GHz (U-NII band 1) and 5.25 to 5.35 GHz (U-NII band 2), which are designated for wireless LAN and other short-range use; and 5.725 to 5.825 GHz (U-NII band 3) for wide-area networking that reaches a greater distance with higher power. From time-to-time the FCC or another regulator may add a U-NII band, e.g. the proposal for a frequency range of 5.470 to 5.725 GHz. The U-NII bands are designated for wideband, high-data-rate digital communications. They are also license-free; no license is required to operate on the U-NII bands. A detailed description of a system allowing to overcome some of these limitations and exploiting the non-license bearing air bands is provided in U.S. patent application Ser. No. 10/282,533, titled System And Method For Wireless Cable Data Transmission.
It would be therefore advantageous to provide a apparatus and a method that would allow such a CATV operator to deliver a data service to areas which are in the proximity of the service area but are not currently reached by a distribution coax cable. It would be further advantageous if such a system would not require additional transmission licenses.